Nationwide incidence of anterior cruciate ligament reconstruction in higher-level athletes in Sweden: a cohort study from the Swedish National Knee Ligament Registry linked to six sports organisations

OBJECTIVE: To determine and compare the incidence rate (IR) of anterior cruciate ligament reconstruction (ACL-R) among higher-level athletes across six sports in the Swedish National Knee Ligament Registry (SNKLR). METHODS: Patient data from the SNKLR, between 2005 and 2020, was linked to team and event data of six sports (football, handball, basketball, ice hockey, floorball and alpine sports) to identify higher-level athletes aged 15-40 with ACL-R. Unadjusted and adjusted IR ratios (IRRs) with 99% CIs were calculated between sports, sex, age and divisions. RESULTS: Female athletes had a 3.3 times higher ACL-R IR compared with males (1.08 vs 0.32, IRR=3.33, 99% CI: 2.65 to 4.19) per 1000 athlete exposures (AE). Basketball had the largest difference in ACL-R IR per 1000 AE between females and males (1.26 vs 0.22, IRR=5.69, 99% CI: 2.79 to 11.60). Female second-division athletes had higher ACL-R IR per 1000 AE compared with female highest-division athletes (1.27 vs 0.76, IRR=1.67, 99% CI: 1.30 to 2.15). No significant association between age and IR was observed. Compared with football, lower ACL-R IR was observed in floorball and ice hockey in females, as well as in floorball, basketball and ice hockey in males. CONCLUSION: Female athletes had higher ACL-R IRs than males and second-division female athletes had higher ACL-R IRs than highest-division female athletes. Lower ACL-R IRs were observed in floorball and ice hockey compared with football for both sexes. The remaining sports had ACL-R IRs similar to football, except basketball where rates were lower for male athletes.